Spinal stenosis, as well as spondylosis, spondylolisthesis, osteoarthritis and other degenerative phenomena may cause back and leg pain. Such phenomena may be caused by a narrowing of the spinal canal by a variety of causes that result in the pinching of the spinal cord and/or nerves in the spine. Fusion of two or more adjacent vertebrae has been to alleviate such back and leg pain. However, fusion of vertebrae can be disfavored because fusion tends to cause degenerative phenomena in the fused vertebrae to migrate to adjacent vertebral components that have not been fused.